Paris Hilton Shares New Photos With Her Baby Phoenix

Paris Hilton can't get enough of her new title -- mom -- sharing more photos of her baby boy, whom she says is her "whole heart."

The reality star/entrepreneur posted a bunch of heart-tugging pics Monday -- or as she puts it Mommy Monday -- starring newborn Phoenix Barron Hilton Reum.

Paris and hubby Carter Reum welcomed the new kid on the block back in January after struggling to get pregnant ... and keeping it a secret from virtually everyone -- even family.